California voters on Tuesday expanded some of the nation’s toughest gun control measures.

Voters approved Proposition 63, banning large-capacity ammunition magazines, requiring background checks for ammunition sales and speeding the seizure of firearms from owners who are no longer allowed to own them.

The initiative builds on limits signed into law earlier this year that also address ammunition sales and ammunition magazines holding more than 10 bullets.

"Ammo is the next great debate, I think, in gun safety in this country," Newsom said during the campaign. "Guns in and of themselves are not dangerous. ... It’s a gun and the ammo that makes it deadly."

The state already has a program to remove guns from people convicted of a felony or a violent misdemeanor, who are found to be mentally unstable, or the subject of a restraining order involving domestic violence.

Proposition 63 includes a new process requiring offenders to give up their weapons as soon as they are convicted. That would help end a lengthy backlog in enforcing the law that has left thousands of guns in dangerous hands, Newsom said.

Under the proposal, California will be required to participate in the federal firearm owners’ background check system, something the state already does voluntarily.

In addition, the ballot measure will require background checks for ammunition dealers.

Gov. Jerry Brown was not the only Democrat to question portions of the initiative pushed by Newsom as part of his Democratic campaign for governor in 2018.

California has long banned new purchases of ammunition magazines holding more than 10 bullets, but previously allowed owners to keep the ones they have. Both the initiative and the new law require owners to surrender those magazines. The new law makes continued possession an infraction similar to a traffic ticket, while the initiative would let prosecutors charge the violation as either an infraction or a misdemeanor.

Both the new law and the initiative require background checks for buying ammunition, but the initiative uses a different process with fewer exceptions. The ballot measure also would require background checks for ammunition dealers and require dealers to report lost or stolen bullets.